Handle covering with vibration-reducing bladder

ABSTRACT

An air isolation hand or handle covering has a bladder consisting of a plurality of interconnected or independent inflation cells that is positioned between the hand and a hand-held tool or other vibrating object. The cells are oriented to permit easy bending of the hand covering in directions appropriate for grasping an object. The effectiveness of the bladder in reducing the vibration energy transmitted to the hand is a function of the bladder material thickness, the shape and configuration of the bladder, the pressure in the bladder, the compressible fluid used, the volume of the bladder, and the grip force and push force used when clasping a tool or other object. The bladder is attached in place by way of an attachment tab which is integrally formed from at least one of the layers of the bladder and extends for at least about one sixth the length of the fluid cavity. Spacing between weld lines which define the inflation cells can be varied such that the thickness of the bladder in an inflated state varies at different inflation cells. The bladder can be filled with air or other fluid during the fabrication of the bladder or it can be inflated or deflated with a small pump and integral air valve connected to one of the air cavities. The covering may include an inflation sensor to indicate when a proper inflation pressure is reached.

This is a continuation in part of application Ser. No. 08/565,921, filedDec. 1, 1995, now U.S. Pat. No. 5,771,490, which is a continuation inpart of application Ser. No. 08/367,468, filed Dec. 30, 1994, now U.S.Pat. No. 5,537,688, issued Jul. 23, 1996.

BACKGROUND OF THE INVENTION

Many individuals are exposed to hand-induced vibration by usinghand-held vibrating or repeated impact-type tools that include, but arenot limited to, chipping hammers, jackhammers, riveters, jackleg drills,rotary grinders and sanders, orbital sanders, chain saws, lawn mowers,and engine-powered string trimmers. Individuals can also be exposed tohand-induced vibration through clasping objects in their hands that arebeing ground, swagged, or repeatedly hammered. Finally, individuals canbe exposed to hand-induced vibration while riding motor cycles, motorbikes, all-terrain vehicles, and other like vehicles.

Individuals who are exposed to hand-induced vibration or repetitiveimpacts over short periods of time can experience tingling and numbnessin the fingers and hand fatigue. If individuals are exposed to highlevels of hand-induced vibration over prolong periods of time,vibration-induced white fingers (VWF) can develop. This disease resultsin a destruction of the small blood vessels in the fingers, and it canbe debilitating and cause severe pain in extreme cases. The occurrenceof tingling, numbness and fatigue in the hand and fingers and of VWF canbe minimized by reducing the levels of vibration energy directed intothe hands of individuals who use vibrating or repeated impact-type handtools or who clasp objects that direct vibration or repetitive impactsinto the hand.

Vibration levels can be reduced by redesigning the tool or object or byplacing a vibration isolation device between the hand and the tool orobject that is being clasped by the hand. One of the methods forreducing the vibration energy directed into the hands has been the useof gloves that have an elastomer, foam or rubberlike material placedbetween the vibrating tool or object and the hand. Another method hasinvolved wrapping the tool handle with an elastomer, foam or rubberlikematerial which performs the same function as performed by the samematerial used in a glove. Hand coverings such as gloves and handlecoverings made with elastomers or rubberlike materials have proven to beineffective in significantly reducing the vibration energy transmittedto hands from vibrating hand tools or objects clasped by the hand. Toimprove the vibration isolation characteristics of gloves withelastomers or rubberlike materials, it is necessary to make theelastomer or rubber pads used in the gloves very thick. This often makesthe glove stiff and very difficult to use in clasping a hand tool orother object. Also, using gloves with thick elastomer or rubber padscauses the hands to become fatigued in a very short period of time.

Use of thick elastomers as tool handle coverings has also beenproblematic. To achieve acceptable comfort in clasping a tool handlewith the hand, the overall diameter of the tool handle with an elastomerpad must be held within specified limits, such as a preferred diameterof 1.5 inches. Thick elastomer pads may be bent or wrapped around smalldiameter handles. Bending or wrapping is often difficult, since thecircumference of the inside of the pad in contact with the handle issubstantially less than the circumference of the outside of the pad incontact with the hand.

To avoid bending or wrapping problems, thick elastomer pads that areused on small-diameter tool handles may be pre-molded or pre-formed intoa cylindrical shape. The pre-molding process is often expensive andrestricts the use of a pre-molded or pre-formed pad to a single-sizehandle and a single handle configuration. In either the wrapped or thepre-molded form, thick elastomers pads used on tool handles also quicklydeteriorate under the severe working conditions in which tools exposedto high levels of vibration are commonly used.

Pre-molded elastomer air bladders have been proposed for use inattenuating shock directed into the hand. The injection mold processused to make pre-molded air bladders is very expensive, and as withpre-molded thick elastomer pads, pre-molded elastomer air bladders arerestricted to single size and single handle configurations. The bladdermaterial of pre-molded elastomer air bladders is usually fairly thick,such as 0.010 inches or thicker. The increased bladder materialthickness significantly reduces the effectiveness of pre-molded airbladders in reducing the vibration transmitted to the hand from a toolhandle.

Regardless of whether thick or thin handle coverings are used, andregardless of whether the covering is formed flat or circular,attachment of the handle covering to the handle may be difficult orinefficient. The handle covering needs to be tightly secured to thehandle so there is no relative movement between the handle and thehandle covering either in a rotational or in an axial sense, while stillpermitting the radial compression needed for adequate vibrationattenuation.

The occurrence of VWF is significantly affected by a cold environment.VWF is more prevalent in areas where workers must work either outside orinside in a cold environment. Gloves are often used in theseenvironments to warm the hands, reducing the effects of cold on theprevalence of VWF in these environments. Using gloves with elastomer orrubberlike pads that are also designed to keep the hands warm createsthe same problems that are associated with gloves that have extremelythick elastomer or rubberlike pads. The gloves tend to be stiff andoften make it difficult to easily clasp a hand tool or other object.

European standards have recently been promulgated which poserequirements for a protection device marketed in Europe to be properlyclassified as a "vibration protection glove" or an "antivibrationglove." These standards are outlined in European Standard prEN ISO 10819(1995), Mechanical Vibration and Shock--Hand-arm Vibration--Method forthe Measurement and Evaluation of the Vibration Transmissibility ofGloves at the Palm of the Hand. To meet the standard, a glove must havean overall time-averaged vibration transmissibility in the frequencyrange from 32 Hz to 200 Hz, TR_(M), of less than 1.0, and an overalltime-averaged vibration transmissibility in the frequency range from 200Hz to 1,250 Hz, TR_(H), of less than 0.6. The vibration transmissibilityin the standard is defined as the ratio of the vibration amplitudedirected into the palm of the hand with the glove divided by thevibration amplitude directed into the palm of the hand without theglove. The standard specifies that vibration transmissibility is to bemeasured while the vibration test handle is being clasped with a gripforce of 5 lb (25 N) and while the hand is pushing on the vibration testhandle with a push force of 10 lb (50 N).

Hand and handle coverings are desired which will more effectively reducethe vibration transmitted to the hand from the hand-held object, andwill furthermore be thin, flexible, thermally insulative and relativelyinexpensive.

SUMMARY OF THE INVENTION

The problems associated with hand and handle coverings that containelastomer or rubberlike pads or that are made from pre-molded airbladders are solved with the air isolation hand and handle coverings ofthe present invention. The air isolation coverings contain a bladdermade from thin, flexible thermoplastic sheet material to be filled withair or other compressible fluid. The bladder has weld lines which definea plurality of interconnected or independent inflation cells, forplacement between the hands and a tool or other object when the handsclasp the object. The bladder is attached by way of a first attachmentportion which is integrally formed from at least one of the layers ofthe bladder and extends for at least about one sixth the length of thefluid cavity. A second attachment portion extending from the other endof the bladder may also be used. In another aspect of the invention,weld line spacing varies such that the thickness of the bladder in aninflated state varies at different inflation cells.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1-1 is a plot of the measured vibration transmissibility of threedifferent air bladder configurations.

FIG. 1-2 is a plot of the measured vibration transmissibility of a 0.17inch thick bladder as a function of bladder material thickness.

FIG. 1-3 is a plot of the calculated vibration transmissibility of a0.375 inch thick bladder as a function of bladder material thickness.

FIG. 2-1 is a plan view of a first embodiment of the air isolation handcovering of the present invention showing the bladder configuration.

FIG. 2-2 is a cross-sectional view of the first embodiment of the airisolation hand covering taken along line 2--2 in FIG. 2-1.

FIG. 3-1 is a plan view of a second embodiment of the air isolation handcovering of the present invention showing the bladder configuration.

FIG. 3-2 is a cross-sectional view of the second embodiment of the airisolation hand covering taken along line 3--3 in FIG. 3-1.

FIG. 4-1 is a plan view of a third embodiment of the air isolation handcovering of the present invention showing the bladder configuration.

FIG. 4-2 is a cross-sectional view of the third embodiment of the airisolation hand covering taken along line 4--4 in FIG. 4-1.

FIG. 5-1 is a plan view of a fourth embodiment of the air isolation handcovering of the present invention showing the bladder configuration.

FIG. 5-2 is a cross-sectional view of the fourth embodiment of the airisolation hand covering taken along line 5--5 in FIG. 5-1.

FIG. 6-1 is a plan view of a fifth embodiment of the air isolation handcovering of the present invention showing the bladder configuration.

FIG. 6-2 is a cross-sectional view of the fifth embodiment of the airisolation hand covering taken along line 6--6 in FIG. 6-1.

FIG. 7 is a cross-sectional view of a three-layer air bladderconfiguration with two adjacent rows of air cells.

FIG. 8-1 is a plan view of a sixth embodiment of a bladder for the airisolation hand covering of the present invention.

FIG. 8-2 is a cross-sectional view of the sixth embodiment of the airisolation hand covering taken along line 8.2--8.2 in FIG. 8-1.

FIG. 8-3 is an uninflated cross-sectional view of FIG. 8-2.

FIG. 8-4 is a cross-sectional view of the sixth embodiment of the airisolation hand covering taken along line 8.4--8.4 in FIG. 8-2.

FIG. 8-5 is an enlarged plan view of a portion of the palm of thebladder of FIG. 8-1.

FIG. 8-6 is a cross-sectional view of the sixth embodiment of thebladder taken along line 8.6--8.6 in FIG. 8-5.

FIG. 8-7 is a cross-sectional view of the sixth embodiment of thebladder taken along line 8.7--8.7 in FIG. 8-5.

FIG. 8-8 is an uninflated cross-sectional view of FIG. 8-7.

FIG. 9-1 is an expanded cross-section view of the tip of the fingershowing the attachment tab.

FIG. 9-2 is an expanded cross-section view of the tip of the fingershowing the attachment tab.

FIG. 9-3 is an expanded cross-section view of the tip of the fingershowing the attachment tab.

FIG. 10-1 is a plan view of a seventh embodiment of a bladder for theair isolation hand covering of the present invention.

FIG. 10-2 is a cross-sectional view of the sixth embodiment of the airisolation hand covering taken along line 10.2--10.2 in FIG. 10-1.

FIG. 10-3 is an enlarged plan view of a portion of the palm of thebladder of FIG. 10-1.

FIG. 10-4 is a cross-sectional view of the seventh embodiment of thebladder taken along either line 10.4--10.4 in FIG. 10-3.

FIG. 10-5 is a cross-sectional view of the seventh embodiment of thebladder taken along line 10.5--10.5 in FIG. 10-3.

FIG. 10-6 is a cross-sectional view of the seventh embodiment of thebladder taken along line 10.6--10.6 in FIG. 10-3.

FIG. 11-1 is a plan view of an eighth embodiment of a bladder for theair isolation hand covering of the present invention.

FIG. 11-2 is a plan view of a portion of the palm of the bladder of FIG.11-1.

FIG. 11-3 is a cross-section view of the bladder taken along line11.3--11.3 of FIG. 11-2.

FIG. 11-4 is a cross-section view of the bladder taken along line11.4--11.4 of FIG. 11-2.

FIG. 12 is a plan view of a ninth embodiment of a bladder for the airisolation hand covering of the present invention.

FIG. 13 is a plan view of a bladder for use in a handle covering of thepresent invention.

FIG. 14 is an end view of the bladder of FIG. 13 around a circularhandle.

FIG. 15 is an end view of the bladder of FIG. 13 around a hexagonalhandle.

FIG. 16-1 is a plan view of an eleventh embodiment of a bladder for usein a handle covering of the present invention.

FIG. 16-2 is a cross-section view of the bladder of FIG. 16-1 takenalong line 16.2--16.2.

FIG. 17 is a cross-section end view of the bladder of FIG. 16-1 around acircular handle.

FIG. 18-1 is a plan view of an eleventh embodiment of a bladder for usein a handle covering of the present invention.

FIG. 18-2 is a cross-section view of the bladder of FIG. 18-1 takenalong line 18.2--18.2.

FIG. 19 is a cross-section end view of the bladder of FIG. 18-1 around acircular handle.

FIG. 20 is an end view of a second alternative bladder configurationaround a circular handle.

FIG. 21 is a side view of a chipping hammer fitted with the handlecovering of FIG. 14.

FIG. 22 is a side view of a horizontal grinder fitted with the handlecovering of FIG. 14.

While the above-identified drawing figures set forth alternativeembodiments, other embodiments of the present invention are alsocontemplated, some of which are noted in the discussion. In all cases,this disclosure presents illustrated embodiments of the presentinvention by way of representation and not limitation. Numerous othermodifications and embodiments can be devised by those skilled in the artwhich fall within the scope and spirit of the principles of thisinvention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

The present invention is a hand and handle covering which uses a bladderinflated with a compressible fluid to reduce vibration transmissionthrough the hand or handle covering, and further provide substantialthermal insulation benefits. While further discussion of the inventionwill refer to "air" as the compressible fluid being used, workersskilled in the art will recognize that any compressible fluid could besubstituted for air within the spirit of the invention.

The effectiveness of an air isolation bladder in reducing vibrationenergy directed into the hand is illustrated in FIGS. 1-1, 1-2 and 1-3.For each of FIGS. 1-1, 1-2 and 1-3, medium frequency range (32 to 200Hz) vibration transmissibility (TR_(M)) and high frequency range (200 to1,250 Hz) vibration transmissibility (TR_(H)) are defined in accordancewith EN/ISO 10819 (1995). The vibration transmissibility in FIGS. 1-1,1-2 and 1-3 is the ratio of the vibration amplitude directed into thepalm of the hand with the bladder divided by the vibration amplitudedirected into the palm of the hand without the bladder. The values arenearly the same for the cases where the bladder is inserted in a gloveor wrapped around a handle.

FIG. 1-1 shows tested vibration transmissibility as a function ofvibration frequency for three different air bladder configurations. Eachof the air bladder configurations consist of a plurality ofinterconnected air cells, similar to those shown in FIGS. 2-6, 8 and 10.The tested bladders had an overall bladder thicknesses when inflated of1/8 in. (3.2 mm), 1/4 in. (6.4 mm), and 3/8 in. (9.5 mm), respectively,and were inflated to pressures of between 5.8 psi (40 kpa) and 11.6 psi(80 kpa). The larger the diameter of the plurality of interconnected aircavities in the bladder, the greater the air volume of the inflatedbladder.

The first embodiment of an air isolation hand or handle covering of thepresent invention is shown in FIG. 2. Glove 10 consists of a palmportion 20, finger stalls 21, 22, 23 and 24, a thumb stall 25, and agauntlet 26. The air isolation glove has an inner liner 12 that is cutand formed into a hand covering structure. The inner liner 12 is of asoft, moisture-absorbing material, such as cotton, GORETEX®, Lycra® orother like material Inner liner 12 provides comfort when placed againsta user's palm, absorbs any sweat from the palm, and helps prevent anyrash or dermatitis from forming on the fingers, thumb, or palm of thehand. The outer covering layer 13 is of a protective, wear-resistantmaterial such as leather, cloth or other like material. Alternatively,the inner liner 12 and the outer covering layer 13 may be of the samematerial, depending on the environment in which the glove will be used.Placed between the inner liner 12 and the outer covering layer 13 in theinside palm portion 20 and finger and thumb stalls 21, 22, 23, 24, and25 is an air bladder 11. If desired the material 14 of the air bladder11 may extend to the back side 15 of the glove 10.

Air bladder 11 includes a plurality of air cavities or cells 112. Cells112 are defined by cell divisions 30, where the inner layer 32 and outerlayer 34 of bladder 11 are joined. Air bladder 11 may be made of anyflexible, air-tight material. The air bladder 11 is preferably made fromtwo layers of a thin thermoplastic material, with the preferredthermoplastic material being ether-based urethane which has a durometerhardness of from 80 to 85.

FIG. 1-2 shows measured values for vibration transmissibility for abladder with an overall thickness of 0.17 inch (4.3 mm), as a functionof the thickness of the bladder material. FIG. 1-3 shows the samevibration transmissibility curves for a bladder with an overallthickness of 0.375 inch (8.6 mm), with the values plotted beingcalculated based on the measured data reported in FIGS. 1-1 and 1-2. Asshown in FIGS. 1-2 and 1-3, even when the overall thickness of thebladder remains constant, the ability of the bladder to attenuatevibration and particularly high frequency vibration changes drasticallyand in a nonlinear fashion based on the thickness of the bladdermaterial used. Regardless of the overall thickness of the bladder, bothtransmissibilities TR_(M) and TR_(H) approach a value of one as thematerial thickness is increased to 0.010 inches, which means that nearlyall of the vibration incident on the bladder is transmitted to the hand.To simultaneously meet the requirements of EN/ISO 10819 (1995) for bothTR_(M) and TR_(H), the thickness of the material for the 0.385 inchbladder should be less than 0.009 inches, and the thickness of thematerial for the 0.17 inch bladder should be less than 0.008 inches. Thepreferred thickness is in the range of about 0.005 to 0.007 inches, withthe most preferred thickness being at about 0.006 inches. Use of amaterial thicker than this preferred range, such as a material of 0.010inches, causes significant degradation of the vibration attenuationproperties of the bladder. Use of a material thinner than 0.005 inchescauses manufacturing and wear problems due to the increase propensity ofthe material to tear or rip during handling.

Depending on the material of air bladder 11, cell divisions 30 may beformed by adhesive, by application of heat and/or pressure to join orweld the material of bladder 11, or by other processes. Air bladder 11is manufactured in a uninflated state by joining the two layers ofthermoplastic. It is preferred that cell divisions 30 be as narrow aspossible, such that inner layer 32 generally defines a flat surfaceadjacent the hand and outer layer 34 generally defines a flat surfacefacing outward from the hand. The material of air bladder 11 shouldgenerally be flexible so that cells 112 can easily conform to objectsclasped by the hand.

Cells 112 are linear, and are generally arranged in a planarconfiguration to cover the surface of palm portion 20, finger stalls 21,22, 23 and 24, and thumb stall 25. Cells 112 may not entirely coverthese surfaces. For instance, only 50% of the palm portion 20 may becovered. Similarly, cells 112 may not cover one or more of thesesurfaces at all. For instance, it may not be necessary to cover fingerstalls 21, 22, 23 and 24. However, substantial coverage is desired forall portions of the hand that will contact the vibrating object.

For many applications, it is unnecessary to include any cells 112 on theback side 15 of the glove 10. However, cells 112 provide significantthermal insulation for the hand, and it may be desired to include cells112 on the back side 15 of the glove 10 for applications in coldenvironments.

The cross-sectional shapes of the air cells 112 can be circular as shownin FIG. 2-2. The cross-sectional shape of the air cells 112 may also betriangular, square, hexagonal, octagonal, etc. The air bladder cavities112 in the palm portion 20 and the finger and thumb stalls 21, 22, 23,24 and 25 can have the same cavity cross-sectional shape (circular,triangular, square, hexagonal, octagonal, etc.) or can have a mixture ofcavity cross-sectional shapes (circular, triangular, square, hexagonal,octagonal, etc.). The cross-sectional dimensions of the air bladdercavities in the palm portion 20 and the finger and thumb stalls 21, 22,23, 24 and 25 can all be the same or they can be different. Thecross-sectional shapes and related dimensions of the air cavities in thepalm portion 20 and the finger and thumb stalls 21, 22, 23, 24 and 25can be varied to permit the air isolation glove to be configured toaccommodate different glove applications.

The cells 112 may be interconnected through air passages 111 or may beindependent. If the cells 112 are independent, they do not communicatewith each other and they each have a certain pressure. Independent aircells 112 will generally be inflated during manufacture of glove 10.

If the air cavities are interconnected, they can be made to communicatewith each other through small air passages 111 that are molded into thebladder. This fluid communication allows bladder 11 to be inflated anddeflated from a single source after manufacture of glove 10. The airpassages 111 can be small orifices between layers 32 and 34 that allowadjacent air cavities 112 to communicate. Air passages 111 can be smallelastic tubes placed between adjacent air cavities 112 that allow themto communicate with each other. The connection of adjacent cells 112 byair passages 111 can allow the air pressure in the plurality ofinterconnected air cavities 112 to adjust or equalize as the glove 10clasps a tool handle or other object. Alternatively, air passages 111may be formed so as to close when glove 10 is flexed or curled about atool handle or other object. These closing air passages 111 allowinflation and deflation of bladder 11 from a single source, but do notallow fluid communication between adjacent cells 112 during use.

Adjacent cells 112 can be parallel to each other or they can be orientedat differing angles relative to each other, as is show in FIG. 2-1 wherethe thumb stall 25 is connected to the palm portion 20. Duringinflation, cells 112 will resist bending or flexing, but cell divisions30 will provide joints which allow bending between cells 112. Theorientation of cells 112 and cell divisions 30 can generally be chosento allow more easy flexing of glove 10 for its intended use. In theconfiguration shown, cell divisions 30 allow ready downward curling offinger stalls 21, 22, 23 and 24. Cell divisions 30 also allow readybending of thumb stall 25 diagonally inward, and allow ready opposablebending between the thumb stall 25 and palm portion 20.

If the air cavities 112 are interconnected, the air bladder 11 can befilled through a small hollow tube 113 attached to the endmost aircavity of the palm section 20 or to any other air cavity. The airbladder 11 can also be inflated with a small manual pump 28 (shownschematically) attached to the hollow tube 113. A check and air-releasevalve 29 (shown schematically) attached between the small manual pump 28and the hollow tube 113 can be used to adjust the interior air pressurein the air bladder 11. Regardless of whether cells 112 are independentor interconnected, bladder 11 may also be inflated and completely sealedduring manufacture having a certain interior air pressure. If bladder 11is completely sealed, it would not be necessary to provide any inflatingvalve or pump.

A second embodiment of the air isolation hand and handle covering isshown in FIG. 3. Mitten 40 consists of a palm portion 20, a fingerportion 42, a thumb stall 25, and a gauntlet 26. With the exception ofthe difference between the finger portion 42 of the second embodiment ofthe present invention and the finger stalls 21, 22, 23 and 24 of thefirst embodiment of the present invention, the construction of thesecond embodiment of the present invention is the same as the first.

A third embodiment of the air isolation hand and handle covering isshown in FIG. 4. Glove 50 consists of a palm portion 20, finger stalls51, 52, 53 and 54, a thumb stall 55, and a gauntlet 26. The constructionof the third embodiment of the present invention is the same as thefirst embodiment of the present invention with the exception the fingerstalls 21, 22, 23 and 24 and the thumb stall 25 are shortened and leftopen so that the fingers and thumb can extend exposed through the endsof the finger stalls 51, 52, 53 and 54 and the thumb stall 55.

A fourth embodiment of the air isolation hand and handle covering isshown in FIG. 5, Mitten 60 that consists of a palm portion 20, a fingerportion 61, a thumb stall 65, and a gauntlet 26. The construction of theforth embodiment of the present invention is the same as the secondembodiment of the present invention with the exception the fingerportion 42 and the thumb stall 25 are shortened and left open so thatthe fingers and thumb can extend exposed through the ends of the fingerportion 61 and the thumb stall 65.

A fifth embodiment of the air isolation hand and tool handle covering isshown in FIG. 6. Mitten 70 consists of a palm portion 20, a fingerportion 42, a thumb stall 25, and a gauntlet 26. The construction of thefifth embodiment of the present invention is the same as the secondembodiment of the present invention with the following exception.Lubricating strips 72 can be attached to the palm portion 20 and thefinger portion 42 of the mitten. Lubricating strips 72 may be thin solidstrips of teflon or other like material.

Lubricating strips 72 allow mitten 70 to slide relative to a vibratinghand-held object, such that the only vibrating forces which aresubstantially transmitted to mitten 70 are those normal to the graspingsurface. Vibratory shear forces are not substantially transmitted tomitten 70, thus increasing the effectiveness of mitten 70. Thisembodiment is particularly useful for applications where the hands areused primarily to push a vibrating object that has substantial vibrationmotion tangent to the palm and finger surfaces of the mitten.

The air bladders 11 in the five embodiments of the present inventionshown in FIGS. 2-6 are composed of a single layer of air cells 112.Alternatively, as shown in FIG. 7, the air bladders 11 in the fiveembodiments of the present invention can include two adjacent layers ofair cells 85. The air bladder 81 in FIG. 7 can be made from three layers82, 83 and 84 of thermoplastic or other similar material that are bondedtogether. The three layers 82, 83 and 84 can be bonded together to formair cells 85 cross-sectional shapes that are circular, triangular,square, hexagonal, octagonal, etc. If interconnection of adjacent cells85 is desired, small orifices in the middle layer 83 can be used toallow air cells 85 to communicate with each other.

A sixth embodiment of the invention is shown in FIGS. 8-1, 8-3, 8-4,8-5, 8-6, 8-7 and 8-8. In this embodiment, glove 120 contains adifferent arrangement and construction of air bladder 124 and pump 128,but otherwise is constructed similarly to the first embodiment.

As best shown in FIGS. 8-2, 8-3 and 8-4, a pocket 122 is defined betweenthe inner liner 12 and the outer covering layer 13, and air bladder 124is inserted into pocket 122.

As best shown in FIG. 8-1, bladder 124 has attachment tabs 126 extendingfrom the tips of the fingers portions 21, 22, 23 and 24. Attachment tabs126 are also located at the sides of the palm section 20, at the base ofthe palm section 20, and at the tip of the thumb portion 25. Attachmenttabs 126 may be stitch tabs which can be punctured without rupturingbladders, thus allowing attachment tabs 126 to be sown in to appropriatelocations of the glove 120. Alternatively, attachment tabs 126 may bebond tabs which attach to appropriate location of the glove 120 byadhesive, thermal or other bonding operations. Attachment tabs 126 areused to fix the position of air bladder 124 in pocket 122.

FIGS. 9-1 through 9-3 show different configurations of the attachmenttabs 126. FIG. 9-1 shows the attachment tab 126 as an extension of airbladder 124 that is directly sewn or bonded into the glove seam 123.FIG. 9-2 shows the attachment tab 126 separated into two parts 125 and127. Part 125 is an extension of air bladder 124. Part 127 is sewn orbonded into the glove seam 123. Parts 125 and 127 are bonded togetherwith a thermo, chemical, adhesive or other bond 129. FIG. 9-3 shows theattachment tab 126 as an extension of air bladder 124 that is directlybonded to the bladder side of the outer covering 13 by a thermo,chemical, adhesive or other bond 129. The attachment tab 126 is FIG. 9-3may also be attached to the bladder side of the inner liner 12.

In contrast to positioning the pump on the gauntlet as in embodimentsone through five, the pump 128 of the sixth embodiment is positioned onthe back side 15 of glove 120. Pump 128 is connected to the small hollowtube inlet 113 of air bladder 124 by inflation line or hose 130. Hose130 is preferably placed around either the radial or ulnar side of thewrist at the base of the palm section 20. Hose 130 should be constructedsturdily enough that it does not crimp or close even upon use of glove120.

Pump 128 consists of an inflation bulb 132, an inflation valve 134 forthe pump to maintain pressure while inflating bladder 124, and a checkvalve 136 so bladder 124 can maintain pressure after inflation. Apressure relief valve 138 opens hose 130 to the atmosphere so the air inbladder 124 can be released when desired.

In contrast to the upward orientation of thumb section as in embodimentsone through five, the thumb section 25 of the bladder 124 of the sixthembodiment is angled downward away from the finger sections 21, 22, 23and 24. Depending on the construction of the glove 120, this downwardorientation of thumb section 25 assists in attaching bladder 124 withinthe glove 120. In cases where glove 120 will be primarily used to hold abar or handle between the thumb and fingers by opposable flexing of thethumb, the downward orientation of thumb section 25 may also assist inplacing bladder 124 over the side of the thumb which makes contact withthe bar or handle.

In the preferred configuration of this sixth embodiment and as best seenin FIGS. 8-6 and 8-7, the cross-sectional thickness of the air bladdercavities 120 in the palm portion 20 and the finger and thumb stalls 21,22, 23, 24 and 25 have a uniform thickness t. The size of this thicknesst is controlled by the spacing of cell divisions 30. However, thisspacing between cell divisions 30 changes upon inflation of the glove.FIGS. 8-7 and 8-8 demonstrate the change in cell division spacingbetween the inflated state shown in FIG. 8-7 and the deflated stateshown in FIG. 8-8. To provide an inflated bladder thickness t within therange of 0.12 in. (3 mm) to 0.38 in. (9.7 mm), the deflated weldlocation spacing s shown in FIG. 8-8 is chosen between 0.23 in. (5.9 mm)and 0.7 in. (17.7 mm). This corresponds to an inflated weld locationspacing s shown in FIG. 8-7 from 0.22 in. (5.5 mm) to 0.6 in. (15.2 mm).The difference between the inflated weld location spacing and thedeflated weld location spacing is due to the curvature of the innerlayer 32 and outer layer 34 upon inflation. Bladder 124 is generallyinelastic, and the surface area of the material of bladder 124 remainsconstant between inflation and deflation, but the curvature of innerlayer 32 and outer layer 34 upon inflation causes weld location spacingto decrease. As a result, the overall surface area of bladder 124,relative to the deflated state, decreases when the bladder is inflated.

The thickness of air bladder 124, inflated to the proper inflationpressure, determines the effectiveness of the bladder in attenuating thetransmission of vibration or shock energy into the palm and fingers ofthe hand. Generally speaking, the thicker the air bladder the moreeffective it is in attenuating vibration or shock energy.

The air bladder 124 is preferably design to have a thickness t withinthe range from 0.12 in. (3 mm) to 0.38 in. (10 mm). Testing hasindicated that the bladder 124 with a thickness of 0.12 in. (3 mm) isthe minimum bladder thickness necessary to sufficiently attenuatevibration to meet the requirements specified in European Standard prENISO 10819 for a glove to be labeled as an antivibration glove. FIG. 1-1indicates the results of such testing. The maximum thickness of the airbladder is primarily constrained by ergonomic, strength and carpaltunnel considerations. The glove 120 of the present invention isdesigned for clasping handles or grips, and the Radwin effect limits thepermissible thickness of the bladder 124. The Radwin effect denotes thatthe forearm strength required to clasp a handle with a constant gripforce increases as the diameter of the handle increases. As the forearmstrength required to clasp a handle increases, the tonic reflex resultsin a corresponding increase in the intracompartmental pressure in thecarpal tunnel. Increased intra-compartmental pressure in the carpaltunnel increases the potential for developing carpal tunnel syndrome.Typical tool handles have an effective diameter that ranges from 0.75in. (19.1 mm) to 1.6 in. (40.6 mm). The placing of an air bladder in aglove between the tool handle and the hand increases the effectivediameter of the tool handle. Along with increasing the potential fordeveloping carpal tunnel syndrome, increasing the effective diameter ofa tool handle can also have a negative effect on being able to properlycontrol a vibrating tool or a tool exposed to shock during its intendeduse. Taking these factors into consideration, the maximum overallthickness of air bladder 124 is 0.38 in. (9.7 mm), while the preferredoverall thickness of air bladder 124 is 0.17 in. (4.3 mm). The measuredmedium and high frequency vibration transmissibility values for thispreferred 0.17 inch (4.3 mm) bladder are shown in FIG. 1-2. FIG. 1-2indicates that for bladder 124 to simultaneously meet the requirementsof EN/ISO 10819 (1995) for both values of TR_(M) and TR_(H), thethickness of the bladder material should be less than 0.008 inches.

The design of glove 120 provides several advantages. A major advantageis due to the use of attachment tabs 126. As discussed earlier, thespacing s between weld locations 30 becomes smaller upon inflation ofbladder 124. The length of the bladder 124 from the base of palm section20 to the tips of finger stalls 21, 22, 23 and 24 includes numerousinflation cells 30, and decreases proportionally upon inflation. Forinstance, the inflated bladder 124 may have a length which isapproximately 85 to 90% of the length of the uninflated bladder. Theglove 120 is generally constructed with an uninflated bladder 124, andattachment tabs 126 provide identifiable benchmarks in construction ofthe glove 120. That is, attachment tabs 126 may be attached to innerlayer 32 and outer layer 34 at locations which correspond with theinflated length of bladder 124. This causes some bunching of bladder 124while uninflated, but provides an inflated glove 120 where the arealsize of bladder 124 matches the areal size of inner layer 32 and outerlayer 34. The bunching may be avoided by folding several of theuninflated inflation cells 112 over on themselves, as shown in FIG. 8-3.

Placement of pump 128 and pressure relief valve 138 on the back side 15of glove 120 provides several advantages. First, gauntlet 26 no longercontains a pump or pressure relief valve, and can be made smaller andmore comfortable. Second, back side 15 is generally more accessiblewhile using the glove and during grasping. The air pressure can be moreeasily adjusted during use of the glove, allowing the air pressure to befelt and monitored by the user in actual working conditions duringadjustment. Also, the air pressure can be easily adjusted, either withthe free hand or by a different person, without halting work by the handusing the glove. Thirdly, grasping with the glove 120 will draw backside 15 taut against the back of the user's hand, firmly seating pump128 against the relatively hard, flat surface. In this position, pump128 can be used simply by pressing on inflation bulb 132, without anyneed to hold or otherwise support inflation bulb 132 with the pumpinghand.

Air bladder 150 shown in FIGS. 10-1, 10-2, 10-3, 10-4, 10-5 and 10-6represents a seventh embodiment of the invention. In many respects theseventh embodiment is identical to the sixth embodiment. However, theweld locations of bladder 150 are markedly different from those ofbladder 124. Bladder 150 has weld locations 152 arranged in a squaregrid pattern, with uniform spacing s between weld locations. The weldpoints 152 can be round, square, triangular, or any other geometricshape. Cell divisions 30 are provided at intervals on the bladder 150through line bonding or welding between the inner layer 32 and outerlayer 34. Line bonds 30 enhance the flexibility and dexterity associatedwith the use of bladder 150.

The grid pattern of weld locations 152 provides additional advantages inthe manufacture and use of bladder 150. The change in spacing betweenweld locations 152 occurs in width as well as in length. This helpsavoid curling problems associated with inflating bladders having linearcells. The absence of curling helps retain a closer feel between bladder150 and inner liner 12 and outer covering layer 13 during inflation ofthe bladder 150. Additionally, line bonds 30 can be placed as desired onbladder 150 without affecting the thickness of any portion of inflatedbladder 150. This allows bladder 150 to have several relatively planarportions connected by separations or joints at locations selected by thedesigner to correspond with the desired flexing of bladder 150, withoutaffecting the uniform thickness of bladder 150. To provide an inflatedbladder thickness t from 0.12 in. (3 mm) to 0.38 in. (9.7 mm), thedeflated weld location spacing s is chosen from a range of 0.18 in. (4.5mm) to 0.5 in. (12.7 mm). This corresponds to a inflated weld locationspacing s shown in FIG. 10-4 of 0.16 in. (4.1 mm) to 0.41 in. (10.4 mm).

Air bladder 160 shown in FIGS. 11-1, 11-2, 11-3 and 11-4 represents aneighth embodiment of the invention. In many respects the eighthembodiment is identical to the seventh embodiment. However, the weldlocations 162 of this embodiment are in the shape of plus signs (+).This provides a grid of rectangular inflation cells 164 interconnectedon each side to adjacent inflation cells 164. With square inflationcells 164 shown in FIGS. 11-1 and 11-2, shrinkage during inflationoccurs equally in both directions, helping to avoid the curling problemsnoted earlier. To provide an inflated bladder thickness t from 0.12 in.(3 mm) to 0.38 in. (9.7 mm), the deflated weld location spacing ischosen between 0.18 in. (4.5 mm) to 0.5 in (12.7 mm). This correspondsto a inflated weld location spacing s shown in FIGS. 11-3 and 11-4 of0.16 in. (4.1 mm) and 0.41 in. (10.4 mm).

Workers skilled in the art will appreciate that other regular orirregular grid patterns may be beneficial. For instance, a triangulargrid pattern may be used. As a second example, a hexagonal honeycombgrid pattern arrangement may be used to provide a bladder without anylinear arrangement of weld locations between cells, thus making thebladder less subject to folding or flexing. Finally, other non-gridpatterns may be used to facilitated flexing in desired locations, suchas with the palm lines of a user's hand. In non-grid configurations, thedesigner may still wish to equalize distances between weld locations toprovide a bladder having a uniform thickness.

Air bladder 170 shown in FIG. 12 represents a ninth embodiment of theinvention. In many respects the ninth embodiment is identical to thesixth embodiment. However, thumb section 172 of air bladder 170 isangled upward rather than downward. Additionally thumb section 172 isrecessed into palm portion 174. As shown, the base 176 of thumb section172 lines up with the middle finger 23 rather than the first finger 24.This allows grasping with bladder 170 with the thumb in an orientationcloser to the middle finger, while continuing to maintain completeseparation between the user's hand and the tool handle due to bladder170.

Air bladders 180, 280 and 310 in FIGS. 13 through 22 represent tenth,eleventh and twelfth embodiments of the invention. FIGS. 13 through 22show air bladders 180, 280 and 310 which can be wrapped around a handle182 or 210 of a tool or other object clasped by the hand that is exposedto vibration or shock.

Air bladder 180 is similar in construction to the palm section 20 of theair bladder 150 shown in FIGS. 10-1 through 10-6. Bladder 180 has weldlocations 184 in a square grid pattern, with uniform spacing betweenweld locations 184. The weld points 184 can be round, square,triangular, or any other geometric shape. Cell divisions 186 areprovided at intervals on the bladder 180 through line bonding or weldingbetween the inner layer 188 and outer layer 190. Line bonds 186 enhancethe flexibility and dexterity associated with the use of bladder 180.Similar to glove embodiments discussed earlier, bladder 180 is inflatedand deflated through a small hollow tube 192. Bladder 180 includesattachment strips 194 and 196 at each end for reliably attaching thebladder 180 around handle 182 or 210. The means of attachment betweenattachment strips 194 and 196 can be fabric hooks or buttons andassociated grommets or loops, thermo or chemical welds, adhesive bonds,ties, straps, sewing, tapes or any other method of attachment. Workersskilled in the art will appreciate that these and other attachmentmechanisms equivalently attach bladder 180 around handle 182.

Air bladder 180 can also be similar in construction to the palm section20 of air bladder 81 shown in FIG. 7, to the palm section 20 of airbladder 124 shown in FIGS. 8-1 through 8-8, or to the palm section 20 ofair bladder 160 shown in FIGS. 11-1 through 11-4, or to any combinationof cell patterns associated with air bladders 81, 124, 150 and 160. Thevibration and shock energy attenuation and related designcharacteristics associated with this embodiment of the invention as theyrelate to protecting the hand from vibration and shock are the largelythe same as those described for embodiments one through nine.

FIG. 14 shows handle covering 220 which is comprised of air bladder 180wrapped around a round handle 182. Handle 182 can also be elliptical orany other curved shape. Air bladder 180 can be wrapped around acircular, elliptical or other curved shaped handle where the only meansof attachment is the connection of attachment tabs 194 and 196 aspreviously described. When this means of attachment is used, a singlebladder 180 can be used on several different vibrating tools, with theuser moving bladder 180 from tool to tool as desired.

Situations often arise where a more substantial means of attaching airbladder 180 to handle 182 exposed to vibration or shock must be used.FIG. 14 shows how bladder 180 can be attached to handle 182 when this isthe case. An inner liner 198 is wrapped around handle 182. The innerliner 198 can be attached to handle 182 by means of a tape with adhesiveor other type of bonding agent on both sides of the tape or it can bebonded directly to handle 182 with an adhesive of other type of bondingagent. The inner liner 198 can be a thin layer of Latex rubber, plasticvinyl sheet, or other similar material that is used as a bonding layerfor the inner layer 188 of bladder 180. The inner layer 188 of bladder180 is bonded to the inner liner 198 by means of an adhesive or othertype of bonding agent along bond or weld lines 199. The purpose of innerliner 198 is to provide a thin bonding layer to prevent bladder 180 fromrotating around handle 182 while bladder 180 is clasped by the hand. Theinner liner 198 can be removed and the inner layer 188 of the bladder180 can be directly attached to handle 182 by tape with adhesive orother type of bonding agent on both sides of the tape or by othersimilar bonding methods. A cover layer 200 can be wrapped around theouter layer 190 of bladder 180. Cover layer 200 can be a thin layer of avariety of soft compliant materials, such as Latex rubber, plastic vinylsheet, molded rubber, leather, elastic tape, non-elastic tape, or othersimilar material. The cover layer 200 can be bonded to outer layer 190of bladder 180 by means of an adhesive or other similar material that isapplied to or is part of the surface of cover layer 200 in contact withthe outer layer 190 of bladder 180 or by means of an adhesive or othertype of bonding agent along bond or weld lines 199. The cover layer 200may also be a section of "shrink" tubing that is slipped over the outerlayer 190 of bladder 180 and then shrunk to conform to the outer layer190 by applying heated air to the shrink tubing. The shrink tubing maybe the type that becomes rigid in its shrunken state or the type thatmaintains its resiliency in its shrunken state. The purpose of the coverlayer 200 is to protect air bladder 180 from excessive wear or damagefrom objects that might come in contact with the handle. This method ofattaching bladder 180 to handle 182 will allow air bladder 180 and otherrelated elements to be easily removed from the handle when a new toolhandle covering 220 must be placed around the handle.

FIG. 15 shows handle covering 230 which is comprised of bladder 180wrapped around a hexagonal handle 210. Hexagonal handle 210 can be anypolygonal shape. The comments made relative to attaching bladder 180 toround handle 182 also apply to attaching bladder 180 to hexagonal handle210. Regardless of the cross-sectional shape of the handle, the flexiblebladders of the present invention allow the handle coverings to beeasily wrapped around the handles.

With small diameter handles, the circumference of the inside of thebladder in contact with the handle is substantially less than thecircumference of the outside of the bladder in contact with the hand. Ifa single celled, flat (not pre-molded), flexible bladder is used, thedifference in circumference causes pinching or compression of the insidesurface of the bladder and stretching or tension of the outside surfaceof the bladder. The compression and tension forces can result inunacceptable wear in the air bladder over time and can also result inpre-mature bladder failures.

One approach to avoid the pinching and stretching caused by bending aflat-formed bladder is to have voids in the bladder that run parallel tothe handle. The voids can be created by cell divisions or weld lines,particularly if the weld lines are fairly wide. The voids allow bendingof the bladder without the buildup of compression and tension forces.However, the voids can allow contact between the handle and the handwhich will significantly reduce the effectiveness of the bladder inreducing vibration transmitted from the bladder to the hand.

It is often preferred to use thick bladders around small-diameterhandles, such that the Wear problems are exacerbated by the bending ofthe thick elastomer pad (formed in a flat condition) into place around asmall diameter tool handle.

Air bladder 280 shown in FIGS. 16 and 17 is somewhat similar inconstruction to the three-layer air bladder 81 shown in FIG. 7. Airbladder 280 includes three layers 282, 283 and 284 of thermoplastic orother similar material that are bonded together along weld lines 30. Thethree layers 282, 283 and 284 form air cells 285 of a generallysemi-circular cross-sectional shape. Small orifices 286 in the middlelayer 283 allow air cells 285 to be interconnected and communicate witheach other.

The two layers of offset air cells 285 of air bladder 280 provide anuninterrupted, continuous layer of air between the hand and the handle182 of a tool or other object that is exposed to vibration or shock. Airbladder 280 thus has no voids between the hand and the handle 182. Theabsence of voids increases the effectiveness of air bladder 280 inreducing vibration or shock directed into the hand from the handle 182.

The two layers of generally semi-circular air cells 285 of air bladder280 also allow a bladder with a larger overall thickness to be usedaround a small-diameter handle. For instance, the overall thickness ofair bladder 280 may be in the range of about 0.25 to 0.5 inches orthicker. If a 0.5 inch thick air bladder 280 is used on a handle with anouter diameter of 1 inch, the outer circumference of the bladder 280will be about 6.25 inches, twice the inner circumference of the bladder280. Despite this large difference in circumference, the air bladder 280of the present invention has excellent wear properties by avoidingexcessive pinching and/or stretching. The semi-circular shape of theinner layer of air cells 285 (i.e., those air cells 285 between insidelayer 284 and intermediate layer 283) allows the air bladder 280 to bebent into a circular configuration without compression of the insidesurface of the bladder 280. Excessive pinching or compression of theinside surface of the bladder 280 is avoided. The weld lines 30separating air cells 285 on the outer layer (i.e., those air cells 285between intermediate layer 283 and outside layer 282) allow the airbladder to bent into a circular configuration without tensioning theoutside surface of the bladder 280. Excessive stretching or tension ofthe outside surface of the bladder 280 is also avoided.

Bladder 280 has an "offset symmetry" about intermediate layer 283, thatis, the air cells 285 on both layers are formed with the same generallysemi-circular shape. Because of the offset symmetry, bladder 280 can bebent into a circular configuration in either direction, that is, bladder280 may also be easily bent in the opposite direction with layer 282forming the inside layer in the circular configuration.

The weld line attachment of layers 282 and 284 to intermediate layer 283determines the cross-sectional shape of the air cells and whether this"offset symmetry" will exist. For instance, the semi-circular shape ofair cells 285 is achieved by having a shorter length of the intermediatelayer 283 between adjacent weld lines 30 than the length of the attachedlayer 282 or 284 between those weld lines 30. This is in contrast to thethree layer configuration shown in FIG. 7, wherein a more triangularcross-sectional shape is provided by having a greater length of theintermediate layer 83 between adjacent weld lines 30 than the length ofthe attached layer 82 or 84 between those weld lines 30.

It is appreciated that other configurations of air cells 285 may beprovided in a three-layer bladder. In particular, by having generallysemi-circular air cells on one side of intermediate layer 283 and havingmore triangular air cells on the other side of intermediate layer 283,the "offset symmetry" will no longer exist and the bladder will have atendency to flex or curl only in one direction.

Air bladder 280 has extension tabs 288 and 290 extending from both endsof the bladder 280. Extension tabs 288 and 290 are preferably integrallyformed from one or more of layers 282, 283 and 284. For instance,extension tabs 288 and 290 may be formed by all three layers 282, 283and 284, joined together by a continuous heat welding/sealing operationused to simultaneously form weld lines 30. Extension tabs 288 and 290preferably extend for at least 60° around handle 182, or for at leastone sixth of the length of the inflated fluid cavity. In the mostpreferred embodiment, extension tabs 288 and 290 extend 360° aroundhandle 182.

Extension tabs 288 and 290 are used to attach air bladder 280 aroundhandle 182, similar to the function performed by the inner liner 198 andcover layer 200 described with reference to FIGS. 14 and 15, and similarto the function performed by attachment tabs 126 described withreference to FIGS. 8 through 11. Extension tab 288 is affixed to handle182, such as by means of an adhesive layer 292. The adhesive layer 292may be a pressure sensitive adhesive which prevents rotation ofextension tab 288 relative to handle 182. The pressure sensitiveadhesive is preferably releasable, to readily allow removal of thebladder 280 from the handle 182 when the bladder 280 is unwound. Such apressure sensitive, releasable adhesive allows the bladder 182 to beeasily transferred between different handles. Alternatively, theadhesive layer 292 may be a setting or curing adhesive which can be usedto permanently attach extension tab 288 to handle 182. The adhesivelayer 292 may be applied along a selected portion or the entirety ofextension tab 288, or may be applied to a selected portion or theentirety of the surface of the handle 182. An attachment length of atleast 60° around handle 182, or at least one sixth of the length of thefluid cavity, has been found to adequately support the shear stressesassociated with the rotational forces applied in most uses, while ashorter length may not adequately attach the bladder 280 to the handle182.

The air bladder 280 is wrapped around the handle 182. The uninflatedlength of the fluid cavity of air bladder 280 should be somewhat longerthan the circumference of the handle 182, as the fluid cavity shortenssomewhat (typically 85 to 95%) upon inflation. In the preferredembodiment, the length of the inflated fluid cavity is the length of thecircumference of the handle plus about six times the thickness of theinner layer of inflation cells 285. This length, when wrapped aroundhandle 182 into the circular configuration shown in FIG. 17, allows bothends of the fluid cavity to contact with each other without overlapping.If desired, an additional layer of adhesive may be applied between theinside surface of the bladder 280 and the outside surface of extensiontab 290.

Extension tab 290 is then wrapped around the outside layer of the airbladder 280 and secured. Preferably, a layer 294 of adhesive between theoutside surface of the bladder 280 and the inside surface of extensiontab 290 secures the bladder 280 in the wrapped position. The compositionfor the adhesive layer 194 for extension tab 290 may be identical to theadhesive layer 292 for extension tab 288. If desired, a cover layer 200may be wrapped around the outside extension tab 290 of bladder 280.

The preferred overall thickness of air bladder 280 is 0.375 in. (9.5mm). The calculated medium and high frequency vibration transmissibilityvalues for this preferred 0.375 inch (9.5 mm) bladder are shown in FIG.1-3. FIG. 1-3 indicates that for bladder 280 to simultaneously meet therequirements of EN/ISO 10819 (1995) for both values of TR_(M) andTR_(H), the thickness of the bladder material should be less than 0.010inches.

An internal inflation check valve 296 is preferably molded into one ofthe air cells 285 of the bladder 280. Locating the inflation check valve296 within the bladder 280 significantly simplifies the designrequirements of the inflation mechanism for the air bladder 280.

An inflation sensor 298 can be used to insure that the air bladder 280is inflated to the correct pressure. The inflation sensor 298 includes asensing element or diaphragm 300 which is open on one side to fluidpressure in the bladder 280. In the preferred embodiment diaphragm is inthe form of a plunger mounted to slide within the housing of inflationsensor 298. A spring 302 or other resilient element biases the diaphragm300 to resist the air pressure in the bladder 280. Air pressure withinthe bladder 280 pushes against the plunger 300. When the air bladder isproperly inflated, the plunger is pushed so as to be visible through asmall hole 304, indicating proper inflation pressure.

The air bladders of embodiments one through eleven have inside andoutside surfaces that are essentially parallel to each other, with auniform thickness throughout. FIGS. 18 and 19 show a twelfth embodimentof the invention, wherein the thickness of a bladder 310 varies alongthe surface of bladder 310. Air cells (such as 312a and 312b) in thecenter of bladder 310 are thicker than air cells (such as 312c and 312d)at the edges of the bladder. The thickness of the air cells 312 isvaried by varying the spacing between the weld lines 30 along thesurface of the bladder 310. The bladder 310 should be used with thethickest area of the bladder 310 absorbing the most force. Bladder 310is particularly useful for tools which require exertion of large pushforces, such as to push the tool into a work piece. The thicker aircells 312 prevent contact between the hand and the handle 182 even whena large push force is applied against them, and thus more effectivelyattenuate vibration in a large push force applications.

FIG. 20 shows handle covering 240 which is comprised of bladder 180wrapped around handle 182 where a rigid outer cover 202 is placed aroundbladder 180. Bladder 180 can be wrapped around handle 182 with orwithout an inner liner 198 and/or an outer covering 200 as described inFIG. 14. The rigid outer cover 202 can be made of molded plastic, thinmetal, composite materials, molded elastomers, or other similarmaterials. The rigid outer cover 202 can be held in place and preventedfrom rotating around bladder 180 by means of an adhesive or bondinglayer between the outer layer 190 of bladder 180 or the outer covering200 between the outer layer 190 of bladder 180 and the bladder side ofthe rigid outer cover 202 or by means of the pressure of the inflatedbladder 180 pushing between the handle 182 and the rigid outer cover202. A rigid outer cover 202 can be placed around a bladder 180 wrappedaround a handle with any curved or polygonal shaped. A rigid outer cover202 can be used when a firm or solid hand grip is necessary for theproper use and control of a tool or other object that is clasped by ahand and that is exposed to vibration or shock. Workers skilled in theart will appreciate that bladders 280 or 310 may easily be substitutedfor bladder 180 in this configuration

FIG. 21 shows an application of handle covering 220 applied to thehandle of a chipping hammer. FIG. 21 shows a pump similar to pump 128shown in FIGS. 8-2 through 8-4 attached to the chipping hammer near tothe tool handle covering 220. Pump 128 with its associated pressurerelief valve 138 can be used to adjust the inflation pressure of bladder180 to suit the needs of the tool operator. Pump 128 is connected totube 192 of bladder 180 by means of hose 130.

FIG. 22 shows an application of handle covering 220 applied to the twohand locations of a horizontal grinder. Two pumps similar to pump 128shown in FIGS. 8-2 through 8-4 are attached to the horizontal grinder atlocations near to each tool handle covering 220. Each pump 128 with itsassociated pressure relief valve 138 can be used to individually controlthe inflation pressure in bladder 180 of each tool handle covering 220to suit the need of the tool operator. Each pump 128 is connected totube 192 of its respective bladder 180 by means of a hose 130. It isalso possible to use a single pump 128 to simultaneously inflate bothbladders 180 of each hand covering 220.

FIGS. 21 and 22 show representative applications of handle covering 220.In addition, handle coverings 230 or 240 can be used, depending on theconfiguration of the tool handle or other object exposed to vibration orshock to which they may be attached. Any of the bladders describedherein may be used in any of the attachment configurations. The methodsdescribed above can be used to apply an appropriately designed handlecovering to any tool handle or other object that is clasped by the handand that is exposed to vibration or shock.

The bladders in handle coverings can also be inflated by means of a pumpthat is not an integral part of the handle coverings as shown in FIGS.21 and 22. A pump similar to pump 128 or other inflation device can beattached to tube 192 in bladder 180 by means of an inflation needlesimilar to ones used to inflate footballs, basket balls, etc. Whenbladder 180 has been inflated to the desired pressure, the inflationneedle is removed from tube 192. The inflation pressure in bladder 180is maintained by means of a check valve placed in tube 192 at the pointwhere the inflation needle is inserted.

The designs of handle coverings 220, 230 and 240 along with air bladders180, 280, 310 and their many possible different cell configurationsprovide several advantages. While the bladders and related handlecoverings can be designed to fit specific handles, they can also be"generically" designed to fit around "classes" of handles. The handlecoverings can be easily attached and removed from handles as needed toperform routine maintenance on tools and to replace damaged handlecoverings. The placement of pump 128 and pressure relief valve 138 closeto the handle coverings on a tool or other object exposed to vibrationor shock makes it convenient and easy for the operator to adjust theinflation pressure of the bladder in the handle covering to meet his/herparticular needs.

The desired inflation pressure of air bladders of the present inventionis between 2.9 psi (20 kPa) and 15 psi (103 kPa). The lower inflationpressure of 2.9 psi (20 kPa) is required to prevent the air bladder fromcollapsing, allowing parts of the hand to make direct contact with avibrating object clasped by the and, when the bladder is squeezed with agrip force of 5 lb (25 N) and/or pushed against the object with a pushforce of 10 lb (50 N). The upper inflation pressure is the pressure thatcan be easily achieved by pumps that can be made an integral part of aglove. Air bladder inflation pressures between 5.8 psi (40 kPa) and 8.7psi (60 kPa) are optimum pressures from an overall design standpointwhen considering pump and air bladder design and desired vibration orshock protection.

The air bladders described in these preferred embodiments of FIGS. 2-18serve as an air spring which is very effective in reducing vibration orimpact energy transmitted to the hand. Referring back to FIG. 1-1, thevibration transmissibility curves illustrate several characteristics ofthe use of an air isolation bladder to reduce the vibration energytransmitted to the hand. Firstly, the effectiveness of the air isolationbladder in reducing vibration energy directed into the hand generallyincreases as the thickness of the air in the bladder increases. The 3/8in. (9.5 mm) thick bladder was generally most effective, while the 1/8in. (3.2 mm) thick bladder was generally least effective. It is believedthat this difference is due in part to a greater volume of air in thelarger diameter bladder, allowing a larger attenuation of vibrationenergy during air compression and expansion.

Secondly, the effectiveness of the air isolation bladder is related tothe frequency of the vibrations. The 1/8 in. (3.2 mm) and 1/4 in. (6.4mm) thick air isolation bladders tested were very effective at reducingvibration energy at frequencies over 300-400 Hz (the effectivenessincreased with increasing diameter of the air bladder cells). They weremoderately effective at frequencies less than 300 Hz. The 3/8 in. (9.5mm) thick bladder was effective at all frequencies shown in FIG. 1-1. Itis believed that the beneficial effect to the air isolation bladder isrelated to the time delay which occurs for air compression forces to betransmitted through the air cells. That is, air within the cell will notcompress uniformly during each vibration cycle. Rather, force istransmitted through the air cell in a compression or sound wave, whichdoes not travel instantaneously and does not compress air uniformlywithin the cell. It is believed that the compression energy of higherfrequency vibrations is not effectively transmitted prior to the nextvibration cycle, and thus high frequency energy is more effectivelydissipated by the air isolation bladders. For lower frequencyvibrations, it is believed that more of the compression energy istransmitted prior to the next vibration cycle, and thus the airisolation bladder does not work as effectively at lower frequencies.

It is believed that all of the particular values for vibrationtransmissibility are dependant upon the particular configuration of theair isolation bladder tested, but that similar characteristics would beobserved in all isolation bladders. For example, bladders with differentcell configurations, such as those shown in FIGS. 2, 8, 10 and 11, butthe same thickness will have similar vibration transmissibilitycharacteristics.

The use of an air bladder to reduce the transmission of vibration andimpact energy directed into the hand provides numerous benefits overprior art elastomeric, foam or rubber filled gloves or handle wraps. Inparticular, the air isolation hand covering has the following propertiesand functions:

1. The air isolation hand and handle covering has vibration isolationproperties that are determined by the shape and configuration of the airbladder, the pressure in the bladder, the volume of the bladder, thecompressible fluid used, and the grip force and push force used whenclasping a tool or other object. Each of these parameters can bemodified as desired for maximum vibration isolation for the particularuse contemplated.

2. The air isolation hand and handle covering can be designed withsufficient air volume and air pressure in the air bladder so that thebladder will always maintain an air layer between the hand and tool orother object, irrespective of the grip and push forces employed duringthe operation associated with using the tool or other similar device.

3. The air bladder in the air isolation hand and handle covering can befilled with air during fabrication of the bladder, or it can be inflatedor deflated by means of a small air pump and integral check andair-release valve connected to one of the air cavities of the bladder.

4. If the air bladder in the air isolation hand and handle covering isinflated by means of a small air pump and integral check and air-releasevalue connected to one of the air cavities of the bladder, the airpressure in the air bladder can be controlled to adapt to the differentneeds of the wearers of the air isolation hand covering or toolapplications for a handle covering.

5. The air isolation hand covering is a lightweight glove that iscomfortable to wear and that easily conforms to the different shapes oftool handles and other objects that may by clasped with the gloves. Thissignificantly reduces the hand fatigue that is often associated withgloves that contain elastomer or rubberlike vibration isolation padsthat are often stiff.

6. The thermoplastic or other flexible material used to construct theair bladder in the air isolation hand covering can also be used tocompletely enclose the fingers and palm of the hand, providing effectivelightweight thermal insulation to keep the hand warm.

7. The air isolation handle covering is a tool handle covering that botheffectively reduces vibration energy directed into the hand and can beeasily fabricated to conform to any tool handle shape.

8. By significantly reducing the vibration energy that is directed intothe hand, the air isolation hand and handle covering can significantlyreduce the tingle and numbness in the fingers and the hand fatigue thatis experience when clasping vibrating hand tools or other vibratingobjects.

9. By significantly reducing the vibration energy that is directed intothe hand, the air isolation hand and handle covering can significantlyreduce the incidence of VWF in worker populations or significantlyincrease the time period before symptoms associated with VWF begin toappear in worker populations.

10. By significantly reducing the vibration energy that is directed intothe hand, the air isolation hand and handle covering can significantlyreduce the discomfort that is associated with working with vibratinghand tools or holding onto vibrating objects.

11. The hand and handle covering meets the requirements of EuropeanStandard prEM-150 10819 (1995) for the covering to be classified as a"vibration isolation" or "antivibration" covering.

Although the present invention has been described with reference topreferred embodiments, workers skilled in the art will recognize thatchanges may be made in form and detail without departing from the spiritand scope of the invention.

What is claimed is:
 1. A handle covering for reducing vibration from being transmitted to a user's hand from a handle, the handle covering comprising:a bladder defining a fluid cavity for retaining compressible fluid, the bladder being formed of a first layer of fluid-impervious material and a second layer of fluid-impervious material sealed together along a peripheral seal, with the fluid cavity formed between the first layer and the second layer within the peripheral seal, the fluid cavity having a first edge and an opposing second edge with an inflated length and an uninflated length between the first edge and the second edge, the bladder being flexible both when inflated and when uninflated to allow the bladder to be wrapped in a circumferential configuration about an axis with its length curved 360° and with the first edge and the second edge extending generally linearly and parallel to the axis of the circumferential configuration; and a first attachment tab integrally formed from at least one of the first layer and the second layer, the first attachment tab extending from one of the first edge and the second edge of the fluid cavity with a length which is at least about one sixth the inflated length of the fluid cavity so when the bladder is wrapped in the circumferential configuration the first attachment tab extends circumferentially at least about 60°, the first attachment tab for attaching the bladder to a handle.
 2. The handle covering of claim 1, wherein the first attachment tab includes a handle facing side, and further comprising:an adhesive layer exposed on the handle facing side of the first attachment tab for adhesively attaching the handle facing side of the first attachment tab to a handle.
 3. The handle covering of claim 1, wherein the first attachment tab includes means for removably attaching the first attachment tab to a handle such that the bladder can be readily moved between handles.
 4. The handle covering of claim 1, further comprising:a second attachment tab integrally formed from at least one of the first layer and the second layer, the second attachment tab extending from the fluid cavity opposite the first attachment tab with a length which is at least about one sixth the inflated length of the fluid cavity so when the bladder is wrapped in the circumferential configuration the second attachment tab extends circumferentially at least about 60°, the second attachment tab for securing the bladder circumferentially around a handle.
 5. The handle covering of claim 4, wherein the second attachment tab includes a fluid cavity facing side, and further comprising:an attachment layer exposed on the fluid cavity facing side of the second attachment tab for attaching the second attachment tab to an outer surface of one of the first layer and the second layer.
 6. The handle covering of claim 5, wherein the attachment layer is an adhesive layer.
 7. The handle covering of claim 5, wherein the attachment layer is a hook and loop fabric.
 8. The handle covering of claim 1 in combination with a handle having a circumference, wherein the uninflated length of the fluid cavity is greater than the circumference of the handle.
 9. The handle covering of claim 8 wherein the inflated length of the fluid cavity corresponds to the circumference of the handle when the inflated fluid cavity is wrapped 360° around the handle such that there is no overlap of the inflated fluid cavity and there is complete coverage of the fluid cavity over the circumference of the handle.
 10. The handle covering of claim 1, wherein the first layer and the second layer are connected together at a plurality of weld lines to form a plurality of inflation cells, wherein thickness of the bladder in an inflated state at any location of the bladder is determined by spacing to adjacent weld lines, and wherein spacing between weld lines varies such that the thickness of the bladder in an inflated state varies at different inflation cells.
 11. The handle covering of claim 1, wherein the first layer and the second layer are connected together at a plurality of weld lines to form a plurality of inflation cells, and wherein the plurality of inflation cells are interconnected so as to allow inflation from a single source.
 12. The handle covering of claim 1, wherein the first layer and the second layer are connected together through a grid pattern of weld points.
 13. The handle covering of claim 1, further comprising:a pump for inflating the bladder in fluid communication with the fluid cavity; and a release valve for releasing compressible fluid from within the bladder in fluid communication with the fluid cavity.
 14. The handle covering of claim 1, further comprising:a pressure sensor in fluid communication with the fluid cavity for indicating whether the bladder is inflated to a sufficient pressure.
 15. The handle covering of claim 1, further comprising:an outer cover placed around the bladder, wherein the outer cover is rigid.
 16. The handle covering of claim 1 wherein the first layer has a thickness of from 0.005 to 0.007 inches.
 17. The handle covering of claim 1 attached around a handle with a handle longitudinal axis such that the first edge and the second edge extend substantially parallel to the handle longitudinal axis.
 18. The handle covering of claim 1, wherein the first layer and the second layer are connected together at a plurality of weld lines to form a plurality of inflation cells, wherein the first layer and the second layer are also connected together through a grid pattern of weld points, and wherein the plurality of inflation cells are interconnected so as to allow inflation from a single source.
 19. A handle covering for reducing vibration from being transmitted to a user's hand from a handle, the handle covering comprising:a bladder defining a fluid cavity for retaining compressible fluid, the bladder being formed of a first layer of fluid-impervious material and a second layer of fluid-impervious material sealed together along a peripheral seal, with the fluid cavity formed between the first layer and the second layer within the peripheral seal, the fluid cavity having an inflated length and an uninflated length, and further comprising an intermediate layer of fluid impervious material between the first layer and the second layer, the intermediate layer being bonded to the first layer at discreet divisions which define a plurality of inflation cells between the first layer and the intermediate layer, and the intermediate layer being bonded to the second layer at discreet divisions which define a plurality of inflation cells between the second layer and the intermediate layer; and a first attachment tab integrally formed from at least one of the first layer and the second layer, the first attachment tab extending from the fluid cavity with a length which is at least about one sixth the inflated length of the fluid cavity, the first attachment tab for attaching the bladder to a handle.
 20. The handle covering of claim 11, wherein the first layer has a thickness of less than 0.010 inches; and whereinthe second layer has a thickness of less than 0.010 inches.
 21. The handle covering of claim 20, wherein the bladder has an overall inflated thickness of 0.5 inches or less.
 22. A handle covering for reducing vibration from being transmitted to a user's hand from a handle, the handle covering comprising:a bladder defining a fluid cavity for retaining compressible fluid, the bladder being formed of a first layer of fluid-impervious material and a second layer of fluid-impervious material sealed together along a peripheral seal, with the fluid cavity formed between the first layer and the second layer within the peripheral seal, the fluid cavity having an inflated length and an uninflated length; a first attachment tab integrally formed from at least one of the first layer and the second layer, the first attachment tab extending from the fluid cavity with a length which is at least about one sixth the inflated length of the fluid cavity, the first attachment tab for attaching the bladder to a handle; and a pressure sensor in fluid communication with the fluid cavity for indicating whether the bladder is inflated to a sufficient pressure, wherein the pressure sensor comprises:a housing; a diaphragm within the housing and open to fluid pressure in the fluid cavity; and a spring biasing the diaphragm against the fluid pressure in the fluid cavity;wherein location of the diaphragm within the housing indicates the fluid pressure in the bladder.
 23. A handle covering for reducing vibration from being transmitted to a user's hand from a handle, the handle covering comprising:a bladder defining a fluid cavity for retaining compressible fluid, the bladder being formed of a first layer of fluid-impervious material and a second layer of fluid-impervious material sealed together along a peripheral seal, with the fluid cavity formed between the first layer and the second layer within the peripheral seal, the first layer and the second layer being connected together along a plurality of weld lines to form a plurality of inflation cells, wherein thickness of the bladder in an inflated state at any location of the bladder is determined by spacing of adjacent weld lines, wherein spacing between weld lines varies such that the thickness of the bladder in an inflated state varies at different inflation cells. 